‘The Secret Circle’ midseason finale airs tonight! We chatted with Britt to find out just how dark Cassie will go.

Up until now, we’ve only gotten a taste of of Cassie’s dark magic on The Secret Circle– but Britt Robertsonpromises that the main course is on its way. “It’s a big thing she struggles with for a while,” Britt tells HollywoodLife.com. “She’ll have to figure out a way to control it or tame it or get rid of it. Either way, she’s going to be battling it.”

Britt is quick to point out that, even though Cassie’s magic is considered “dark,” that doesn’t mean it’s necessarily a bad thing — for now.

“It seems evil, but she’s using it for good,” Britt explains. “Where it’ll get sticky is when it starts to get stronger and it gets out of control. Then, she’s unable to determine if she’s using it for good or for bad.”

But regardless of what happens to Cassie, Britt says she’s having a blast getting in touch with her darker side.

“It’s so different from how I’ve been playing Cassie up until now,” she tells us. “It’s cool to see her go from one extreme to the next. That’s a really fun thing for an audience to watch and for an actor to play. I’m having a lot of fun with it.”